The effects of internal resonances in vibration isolators under absolute velocity feedback control

Conventional vibration isolators are usually assumed to be massless for modelling purposes, which tends to overestimate the isolator performance because the internal resonances (IRs) due to the inertia of the isolator are neglected. Previous research on the IR problem does not clarify all the characteristics of distributed parameter isolators. Furthermore, with the development of active vibration isolation, which can avoid the compromise in the choice of damping in conventional passive isolation systems, the effects of IRs in isolators on the control performance and stability for commonly used control strategies need to be quantified. In this study the effects of IRs on the control performance and stability of an absolute velocity feedback (AVF) control system are presented. A stability condition for AVF control system is proposed and a simple approach to stabilize the control system is studied. Experimental work to validate the theoretical results is also presented

Maine gay symposium stresses two themes: a re-evaluation of the homosexual self-image and \u27coming out\u27

Homosexuality and gay liberation are symptoms of a sexually healthy society, said activist Morty Manford at the Maine Gay Symposium here Saturday. Over 300 paying observers attended the well-organized gathering which met with no violent opposition, picketing, or demonstrations as had been feared by some UMO administrators. A team of four campus policemen guarded the affair which was sponsored by the Wilde-Stein Club, UMO\u27s gay group

Purposely Changing Church Culture when a Pandemic Forces Church Change: How the COVID Pandemic Impacted One Large SDA Church

T he Carmichael SDA Church, located in the suburbs of Sacramento, California, seemed to be a gem in the Northern California Conference, with the largest membership, highest tithe, and largest pastoral staff. The pandemic put a halt to most of this church’s ministry, exposing some weaknesses and preventing the ministry it had developed over the years. Simultaneously, new forms of ministry sprung forth because of the sudden changes. The long-term impact of the pandemic challenges this church to move forward in new ways rather than attempting a restart as though nothing happened. This is a case study of how one congregation responded to the COVID-19 pandemic

Machine learning assembly landscapes from particle tracking data

Bottom-up self-assembly offers a powerful route for the fabrication of novel structural and functional materials. Rational engineering of self-assembling systems requires understanding of the accessible aggregation states and the structural assembly pathways. In this work, we apply nonlinear machine learning to experimental particle tracking data to infer low-dimensional assembly landscapes mapping the morphology, stability, and assembly pathways of accessible aggregates as a function of experimental conditions. To the best of our knowledge, this represents the first time that collective order parameters and assembly landscapes have been inferred directly from experimental data. We apply this technique to the nonequilibrium self-assembly of metallodielectric Janus colloids in an oscillating electric field, and quantify the impact of field strength, oscillation frequency, and salt concentration on the dominant assembly pathways and terminal aggregates. This combined computational and experimental framework furnishes new understanding of self-assembling systems, and quantitatively informs rational engineering of experimental conditions to drive assembly along desired aggregation pathways. © 2015 The Royal Society of Chemistryope

Dissociation of structural and functional integrities of the motor system in amyotrophic lateral sclerosis and behavioral-variant frontotemporal dementia

Background and Purpose: This study investigated the structural and functional changes in the motor system in amyotrophic lateral sclerosis (ALS; n=25) and behavioral-variant fronto-temporal dementia (bvFTD; n=17) relative to healthy controls (n=37). Methods: Structural changes were examined using a region-of-interest approach, applying voxel-based morphometry for gray-matter changes and diffusion tensor imaging for white-matter changes. Functional changes in the motor system were elucidated using threshold-tracking transcranial magnetic stimulation (TMS) measurements of upper motor-neuron excitability. Results: The structural analyses showed that in ALS there were more white-matter changes in the corticospinal and motor-cortex regions and more gray-matter changes in the cerebellum in comparison to controls. bvFTD showed substantial gray- and white-matter changes across virtually all motor-system regions compared to controls, although the brainstem was affected less than the other regions. Direct comparisons across patient groups showed that the gray- and white-matter motor-system changes inclusive of the motor cortex were greater in bvFTD than in ALS. By contrast, the functional integrity of the motor system was more adversely affected in ALS than in bvFTD, with both patient groups showing increased excitability of upper motor neurons compared to controls. Conclusions: Cross-correlation of structural and functional data further revealed a neural dissociation of different motor-system regions and tracts covarying with the TMS excitability across both patient groups. The structural and functional motor-system integrities appear to be dissociated between ALS and bvFTD, which represents useful information for the diagnosis of motor-system changes in these two disorders

External muscle heating during warm-up does not provide added performance benefit above external heating in the recovery period alone

Having previously shown the use of passive external heating between warm-up completion and sprint cycling to have had a positive effect on muscle temperature (T m) and maximal sprint performance, we sought to determine whether adding passive heating during active warm up was of further benefit

Early Timeline of Lean Tissue Mass and Strength Improvements in Trained Men Following a High Volume/Frequency Resistance Training Program

International Journal of Exercise Science 12(4): 1094-1109, 2019. The purpose of this study was to determine the early timeline effect of a systemic high volume/frequency resistance training intervention on lean tissue mass and strength in trained men. Twenty-two healthy resistance trained men, age (32.29 ± 9.75 years), training age (9.40 ± 6.18 years) were placed on a 4-week resistance training (RT) intervention with lean mass and strength assessed pre, mid, and post intervention. RT consisted of 6 exercises: flat smith chest press, pull ups, triceps pushdowns, dumbbell bicep curls, leg press or walking lunges, and standing calf raises, completing 5 sets of 6-12 repetitions, 6 days per week. One-way repeated measure ANOVA’s were conducted to determine the impact of time on lean mass, leg press 1-RM, chest press 1-RM, and absolute/relative resistance training volume. Lean mass increased pre to mid 1.27 ± 1.18 kg, (2.03%), mid to post 1.14 ± 1.16 kg, (1.78%), and pre to post 2.41 ± 1.29 kg, (3.84%). Leg press 1-RM increased pre to mid 16.08 ± 34.90 kg, (6.09%), mid to post 27.53 ± 27.69 kg, (9.82%), and pre to post 43.61 ± 40.13 kg, (16.42%). Chest press 1-RM increased pre to mid 5.77 ± 5.51 kg, (4.45%), mid to post 6.70 ± 5.83 kg, (4.94%), and pre to post 12.47 kg ± 5.83 kg, (9.62%). High volume/frequency resistance training results in significant early improvements in lean mass and strength in trained men

Future role of the District Health Authority: assessing needs for services and setting priorities

The purchaser/provider split within the NHS has highlighted the role of District Health Authorities (DHAs) in assessing health needs and buying services to meet those needs. This requires a consideration of what is meant by “need” and how it relates to a system of priorities for health care provision. In the long-term it is to be hoped that DHAs have at their disposal cost-effectiveness information relating to a wide range of interventions, enabling them to make priority decisions. In the short-term, however, a less ambitious aim is to ask what information is currently available which could inform the purchasing role. In areas where data are clearly deficient, this could involve assessing the potential usefulness of available information, assuming that the underlying data could be improved. The starting point for the project upon which this paper is based was therefore to establish the baseline characteristics of participating DHAs’ resident populations, using data already available nationally and locally, supplemented by local survey work where applicable. The aim was to evaluate existing data sources, examining their usefulness in assessing health needs and in making the link from needs to service provision. There is of course no magical formula which translates the identification of needs into what health care services should be provided. Nevertheless this is exactly the challenge faced by those who will be involved in the contractual process.District Health Authority

Effect of combinations of passive and active warming on muscle temperature and sprint performance

Muscle temperature (Tm) has a significant effect on muscle function, force and power production [1], hence the adoption of warm up procedures before power based events. In the majority of sprint or power based events there are periods of maximal activity interspersed with periods of low or no activity, during which Tm may decline, adversely affecting subsequent performance. We have previously shown that Tm will decline during 30 minutes of inactivity following the completion of a warm up, and that the use of passive external heating between warm up completion and sprint cycling performance reduces Tm decline and improves peak power output [2]. The aim of the present study was to follow on from our first Tm study and determine whether, apart from using the electrical heating between warm up and event, there is an additional benefit of using the electrical heating during warm up completion on muscle temperature and subsequent measures of sprint cycling performance. The secondary goal was to look at the efficacy of a redesigned heating system covering a larger area of muscle than in [2]